Question

Which of the following techniques serve the purpose of early diagnosis? (i) R-DNA technology (ii) PCR (iii) ELISA (iv) Conventional method of diagnosis (serum, urine analysis, etc.)
A. (i), (ii) and (iii)
B. Only (iv)
C. Only (iii)
D. All of these

Answer 1

Hint: Early detection of disease often leads to more cures or longer chances of survival. This possibility has led to public health programs which recommend us to have periodic screening to detect chronic diseases. Early diagnosis of diseases can be done with the help of modern technologies. In conventional methods, the markers appear much later.

Complete answer:
Recombinant DNA technology or R-DNA technology puts together DNA molecules from two different organisms to create new genetic combinations and are introduced into the host organism. It may provide reliable information on genetic disorders for diagnosis purposes. PCR or Polymerase Chain Reaction involves amplification of the pathogen's nucleic acid, allowing the pathogen to be identified. In suspected AIDS patients, PCR is used to detect HIV and in suspected cancer patients to detect gene mutations. Whereas, ELISA or Enzyme-Linked Immunosorbent Assay is based upon antigen-antibody reactions. By detecting the presence of antigens (pathogen proteins) in the patient's serum, or by detecting antibodies produced against the pathogen, ELISA may diagnose infections. An early diagnosis opens the door to future care and treatment. It helps people to plan ahead while they are still able to make important decisions on their care and support needs and on financial and legal matters.

So, the correct answer is option A.

Note: Early detection of the disease is not feasible using the traditional form of diagnosis as markers appear late for most diseases. These processes involve serum examination, urine culture etc. ELISA is of different types; direct ELISA, indirect ELISA, sandwich ELISA, etc.